Folic acid is involved in the transfer of single carbon units or methyl groups in various key cellular reactions. In humans, folate deficiency can lead to megaloblastic anemia and developmental neural malformations. Also it may complicate disease states where there is accelerated erythropoiesis due to an increased destruction of red blood cells, like in sickle cell anemia. Deficiency of folic acid may limit the supply of methyl groups for methylation reactions in the cell. Whether methylation is involved in the ineffective hematopoiesis observed during folate deficiency is not known. The recently developed animal models for sickle cell anemia and megaloblastic anemia which closely resemble these diseases in humans could help answer some of these questions. The animals will be made folate deficient by feeding them an amino acid-based, folate-free diet. The effect on methylation and globin gene expression can be assessed. The specific aims of this proposal are to study total methylation capacity of the cell, methylation status of DNA, and its correlation to globin gene expression, globin chain synthesis rates, relative amounts of mouse and human sickle hemoglobins and erythrocyte sickling. Hopefully these studies will contribute to a better understanding of the pathophysiology and interaction of folate deficiency and sickle cell disease.